A man was driving down the road and broke down near a monastery. He went to the monastery and knocked on the door. An elderly monk answered the door, and he said, "My car broke down. Do you think I could stay the night?"

The monks graciously welcomed him into the monastery, fed him dinner, even fixed his car. As the man tried to fall asleep, he heard a strange sound. The next morning, he asked the monks what the sound was, but they said, "We can't tell you. You're not a monk." The man was disappointed, but thanked them and went on his way.

Some years later, the same man broke down in front of the same monastery. The monks welcomed him, fed him, even fixed his car. That night, he heard the same strange noise that he had heard years earlier. The next morning, he asked what the noise was, but the monks replied, "We can't tell you. You're not a monk." The man said, "All right, all right. I'm dying to know. How do I become a monk?"

The monks replied, "You must travel the Earth and tell us how many blades of grass there are and the exact number of sand pebbles. When you find these numbers, you will become a monk."

The man set about his task. Forty-five years later, he returned and knocked on the door of the monastery.

He said, "I have traveled the Earth and have found what you have asked for. There are 145,236,284,232 blades of grass and 231,281,219,999,129,382 sand pebbles on the Earth."

The monks replied, "Congratulations. You are now a monk. We shall now show you the way to the sound."

The monks led the man to a wooden door, where the head monk said, "The sound is right behind that door."

The man reached for the knob, but the door was locked. He said, "Real funny. may I have the key?" The monks gave him the key, and he opened the door.

Behind the wooden door was another door made of stone. The man demanded the key to the stone door. The monks gave him the key, and he opened it, only to find a door made of ruby. He demanded another key from the monks, who provided it. Behind that door was another door, this one made of sapphire. So it went until the man had gone through doors of emerald, silver, topaz, and amethyst.

Finally, the monks said, "This is the last key to the last door." The man was relieved to no end. He unlocked the door, turned the knob, and behind that door he was amazed to find the source of that strange sound. But I can't tell you what it was because you're not a monk.